The present disclosure relates to an electrostatic latent image developing toner.
From a viewpoint of energy saving and apparatus miniaturization, a toner should preferably have excellent low-temperature fixability such as to be favorably fixable with minimal heating of a fixing roller. In order to produce a toner having excellent low-temperature fixability, it is common to use a binder resin having a low melting point or glass transition point, and a releasing agent having a low melting point. Therefore, when such a toner is stored at high temperatures, a problem occurs of toner particles in the toner having a high tendency to aggregate. Aggregated toner particles tend to have a reduced electrostatic charge compared to other toner particles that are not aggregated.
In order to achieve objectives of excellent fixability even at low temperatures, improved preservability at high temperatures, and improved toner blocking resistance, a toner such as described below is used. Specifically, the toner includes toner particles that each have a core-shell structure in which a toner core is coated by a shell layer. In a toner such as described above, the toner cores contain a binder resin having a low melting temperature. The shell layers are made from a resin that has a higher glass transition point (Tg) than the binder resin included in the toner core.
As an example of a toner including toner particles having a core-shell structure such as described above, a toner has been proposed in which toner cores having a softening temperature of no less than 40° C. and no greater than 150° C. while in a uncoated state, are each coated by a thin film containing a thermosetting resin.